STATEN ISLAND, N.Y. -- A five-year project to replace the upper roadway of the Verrazano-Narrows Bridge and add a reversible HOV lane is closer to reality.

A $235 million contract to replace the upper level's deck has been awarded to a Westchester firm, the MTA announced -- and preparatory work is already under way.

As part of the redesign project, the upper level's median will be converted to an HOV lane. The existing service sidewalks on either side of the bridge will be eliminated. When finished, the reversible HOV lane will allow for a seamless link between the Staten Island Expressway and Gowanus Expressway HOV lanes, potentially scoring a smooth commute to and from Manhattan for 30,000 daily express bus riders.

It's a high-tech project: the new orthotropic deck is a continuous structure, made of lighter-weight steel. Without expansion joints that can leak and deteriorate, the new deck is expected to have a longer life span than the original 1964 deck that's still in place. San Francisco's Golden Gate Bridge was given such a deck in 1985, 48 years after it opened.

"The advantages of an orthotropic deck versus a traditional concrete deck are that orthotropic decks are a more durable, lighter and stiffer deck system, improving seismic and wind performance of the bridge," Verrazano-Narrows Facility Engineer David Riggs said.

There will be regular lane closures to contend with when the construction gets under way in 2014, but the MTA is aiming to minimize disruptions, especially during rush hours. For example, throughout the project, all of the bridge's Brooklyn-bound lanes will be available weekdays from 5 to 10 a.m., and all Staten Island-bound lanes will be open from 3 to 7 p.m.

The prep work that has already started and includes the construction of the work platform beneath the upper level deck. The MTA reports that the work is taking place during normal lower level maintenance closures.

In addition, in 2013 motorists may encounter limited off-peak daytime lane closures as the contractor does surveying and painting, and takes field measurements.

The MTA reports that a prototype of the new deck underwent years of rigorous testing and "successfully endured more than 5 million cycles of simulated truck traffic loading" at a Lehigh University engineering research center.

Westchester-based Tutor Perini has been awarded the contract, which will also include a new drainage system, new steel sign structures, new LED lighting on both levels of the bridge, and painting of the support structures.

A separate contract will be awarded later this year for construction of a new ramp on the Brooklyn side of the Verrazano that will connect the bridge's HOV lane to the Gowanus HOV lane.---Follow @siadvance on Twitter